Can anyone help with fuel pump adjustments? An emission test showed Opacities at 45%-50% after a backyard mechanic tampered with the pump a few months ago. It was showing opacities of 8-10% a year ago. I changed the oil, new air filter. Any other suggestions?

I'd like to know more about the pump and any adjustments I can make to the factory Bosch pump. I know it sounds like a million dollar question, but if you can keep it simple, I'd appreciate some help.

Thanks !

 

What does the Opacities test???

 

Opacities is the amount of particulates in the exhaust

Try running a good additive like stanadyne for a couple tankfuls and then re-test. You may also need to adjust the AFC to come on to full fuel later in the curve. If you can get ahold of some bio diesel you may pass with flying colors no matter how much fuel you are burning.

 

Sounds like your mechanic may have cranked the starwheel up especially if you're failing during the snap test, where they floor the pedal from an idle.
To correct this you need to remove the large allan headed plug at the top rear of the injection pump, don't lose the washer under it. After the plug is removed turn the top of the starwheel away from the engine with a screwdriver to about the middle of the plug opening. If you turn it too far your truck will be a dog when accelerating, you'll need to turn it back forward.